Are gay men more at risk of throat cancer because of the sexual practice of fellatio?

That became a reasonable question after the revelation by actor Michael Douglas, star of the Liberace bio-pic on HBO, “Behind the Candelabra,” that throat cancer he battled in recent years was caused by the human papilloma virus (HPV), which can be transmitted via oral sex. Dr. Jeffrey Klausner, professor at the David Geffen School of Medicine at UCLA, notes there’s been a spike HPV-related throat cancer since the 1980s, now eclipsing HPV-related cervical cancer in women, and that twice as many men are developing HPV-associated throat cancer than women.

One recent article was skeptical of Douglas’s suggestion that cunnilingus could have been the transmission route because the act doesn’t create contact to the back of the throat. The implication was that gay men (and women) who perform fellatio may be at higher risk since there’s more back-of-the-throat action.

But Klausner, an infectious disease specialist, strongly disagreed, explaining that HPV is easily transmitted, and even deep kissing is a risk factor. And straight men, he noted, actually seem to have a slightly higher prevalence of oral HPV infection than gay men.

“There’s very good evidence that exclusively heterosexual men can have oral HPV infection,” Klausner said in an interview on my SiriusXM OutQ program, calling HPV “the genital cold,” and noting that most sexually-active people have evidence of HPV antibodies. “The CDC does a large study every year. They actually did an oral HPV survey in 2009 and 2010. And they looked at men who had same-sex partners and they looked at men who had opposite-sex partners. Of course, there may be biases about what people might report to government survey people. But it was a very large study. And what they found was that the positivity rate was the same if not a little bit higher in heterosexual men. Heterosexual men had seven and half percent positivity and men who have sex with men had a 7.1 percent positivity.”

"I would have thought, if there was an important role of same-sex behavior and the performance of fellatio,” he continued, “that we would see dramatically different numbers, similar to how we see dramatically different numbers with anal HPV. Men who have sex with men have much higher rates of anal HPV than heterosexual men do. So it appears that you can actually acquire oral HPV from performing cunnilingus and also deep kissing -- it is a fairly easily spread STD.”

Klausner noted that the though there’s been an increase in HPV-associated throat cancer, it’s still fairly uncommon and said that the reason it’s eclipsing cervical cancer is due to increased screening for and prevention of cervical cancer.

“There’s about twice as many men who may have throat cancer as women,” he said. “There’s been an increase in HPV-related throat cancers since the mid-1980s. It’s still fairly uncommon. We’re talking about thousands -- three to five thousand cases a year. Much less common than breast cancer, colon cancer, other cancers that we hear about. But throat cancer in 2010 eclipsed cervical cancer. So, because of cervical cancer prevention programs and routine screenings, throat cancer is actually more common than cervical cancer. And everyone’s heard of cervical cancer but few people have heard of throat cancer and even fewer know that HPV causes throat cancer.”

Klausner explained that HPV usually clears the body after infection. “It does appear to be dynamic,” he said. “You acquire it. It lasts from days to months and then you clear it.” But though there are vaccines available, there haven’t been studies to show if they would protect people who’ve already been infected and cleared the virus.

“It’s an open question,” he said. “Right now the vaccine is recommended for persons up to age 26. Vaccine uptake in the U.S. is still dismal. Less than 20% of boys and about 40% of girls have been vaccinated. There’s nothing real magic about the age of 26, except when they did the cost effective analysis that’s the break point where they decided it made sense economically. But on an individual basis, if you haven’t been particularly sexually active, there still may be individual benefit. And if it is one of these viruses that you can be exposed to and clear and exposed to again and clear, would the vaccine have benefit? No one has studied that, so we don’t know.”